#include<iostream>
#include<fstream>
#include<string>
#include<vector>
#include<regex>
#include<sys/stat.h>
#include"../server.hpp"


#define DEFAULT_TIMEOUT 10


std::unordered_map<int,std::string> _statu_message = 
{
    {100,  "Continue"},
    {101,  "Switching Protocol"},
    {102,  "Processing"},
    {103,  "Early Hints"},
    {200,  "OK"},
    {201,  "Created"},
    {202,  "Accepted"},
    {203,  "Non-Authoritative Information"},
    {204,  "No Content"},
    {205,  "Reset Content"},
    {206,  "Partial Content"},
    {207,  "Multi-Status"},
    {208,  "Already Reported"},
    {226,  "IM Used"},
    {300,  "Multiple Choice"},
    {301,  "Moved Permanently"},
    {302,  "Found"},
    {303,  "See Other"},
    {304,  "Not Modified"},
    {305,  "Use Proxy"},
    {306,  "unused"},
    {307,  "Temporary Redirect"},
    {308,  "Permanent Redirect"},
    {400,  "Bad Request"},
    {401,  "Unauthorized"},
    {402,  "Payment Required"},
    {403,  "Forbidden"},
    {404,  "Not Found"},
    {405,  "Method Not Allowed"},
    {406,  "Not Acceptable"},
    {407,  "Proxy Authentication Required"},
    {408,  "Request Timeout"},
    {409,  "Conflict"},
    {410,  "Gone"},
    {411,  "Length Required"},
    {412,  "Precondition Failed"},
    {413,  "Payload Too Large"},
    {414,  "URI Too Long"},
    {415,  "Unsupported Media Type"},
    {416,  "Range Not Satisfiable"},
    {417,  "Expectation Failed"},
    {418,  "I'm a teapot"},
    {421,  "Misdirected Request"},
    {422,  "Unprocessable Entity"},
    {423,  "Locked"},
    {424,  "Failed Dependency"},
    {425,  "Too Early"},
    {426,  "Upgrade Required"},
    {428,  "Precondition Required"},
    {429,  "Too Many Requests"},
    {431,  "Request Header Fields Too Large"},
    {451,  "Unavailable For Legal Reasons"},
    {501,  "Not Implemented"},
    {502,  "Bad Gateway"},
    {503,  "Service Unavailable"},
    {504,  "Gateway Timeout"},
    {505,  "HTTP Version Not Supported"},
    {506,  "Variant Also Negotiates"},
    {507,  "Insufficient Storage"},
    {508,  "Loop Detected"},
    {510,  "Not Extended"},
    {511,  "Network Authentication Required"}
};


std::unordered_map<std::string,std::string> _mime_message=
{
    {".aac",        "audio/aac"},
    {".abw",        "application/x-abiword"},
    {".arc",        "application/x-freearc"},
    {".avi",        "video/x-msvideo"},
    {".azw",        "application/vnd.amazon.ebook"},
    {".bin",        "application/octet-stream"},
    {".bmp",        "image/bmp"},
    {".bz",         "application/x-bzip"},
    {".bz2",        "application/x-bzip2"},
    {".csh",        "application/x-csh"},
    {".css",        "text/css"},
    {".csv",        "text/csv"},
    {".doc",        "application/msword"},
    {".docx",       "application/vnd.openxmlformats-officedocument.wordprocessingml.document"},
    {".eot",        "application/vnd.ms-fontobject"},
    {".epub",       "application/epub+zip"},
    {".gif",        "image/gif"},
    {".htm",        "text/html"},
    {".html",       "text/html"},
    {".ico",        "image/vnd.microsoft.icon"},
    {".ics",        "text/calendar"},
    {".jar",        "application/java-archive"},
    {".jpeg",       "image/jpeg"},
    {".jpg",        "image/jpeg"},
    {".js",         "text/javascript"},
    {".json",       "application/json"},
    {".jsonld",     "application/ld+json"},
    {".mid",        "audio/midi"},
    {".midi",       "audio/x-midi"},
    {".mjs",        "text/javascript"},
    {".mp3",        "audio/mpeg"},
    {".mpeg",       "video/mpeg"},
    {".mpkg",       "application/vnd.apple.installer+xml"},
    {".odp",        "application/vnd.oasis.opendocument.presentation"},
    {".ods",        "application/vnd.oasis.opendocument.spreadsheet"},
    {".odt",        "application/vnd.oasis.opendocument.text"},
    {".oga",        "audio/ogg"},
    {".ogv",        "video/ogg"},
    {".ogx",        "application/ogg"},
    {".otf",        "font/otf"},
    {".png",        "image/png"},
    {".pdf",        "application/pdf"},
    {".ppt",        "application/vnd.ms-powerpoint"},
    {".pptx",       "application/vnd.openxmlformats-officedocument.presentationml.presentation"},
    {".rar",        "application/x-rar-compressed"},
    {".rtf",        "application/rtf"},
    {".sh",         "application/x-sh"},
    {".svg",        "image/svg+xml"},
    {".swf",        "application/x-shockwave-flash"},
    {".tar",        "application/x-tar"},
    {".tif",        "image/tiff"},
    {".tiff",       "image/tiff"},
    {".ttf",        "font/ttf"},
    {".txt",        "text/plain"},
    {".vsd",        "application/vnd.visio"},
    {".wav",        "audio/wav"},
    {".weba",       "audio/webm"},
    {".webm",       "video/webm"},
    {".webp",       "image/webp"},
    {".woff",       "font/woff"},
    {".woff2",      "font/woff2"},
    {".xhtml",      "application/xhtml+xml"},
    {".xls",        "application/vnd.ms-excel"},
    {".xlsx",       "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"},
    {".xml",        "application/xml"},
    {".xul",        "application/vnd.mozilla.xul+xml"},
    {".zip",        "application/zip"},
    {".3gp",        "video/3gpp"},
    {".3g2",        "video/3gpp2"},
    {".7z",         "application/x-7z-compressed"}
};

class Util
{
    public:
        //字符串分割
        //将src字符串按sep分割 得到的字串放到array
        static size_t Split(const std::string &src,const std::string &sep,std::vector<std::string> *array)
        {
            size_t offset = 0; 
            while(offset<src.size())
            {
                //在src的offset偏移量处开始查找sep字串 返回查找到的位置
                size_t pos = src.find(sep,offset);
                if(pos ==std::string::npos)
                {
                    //没有找到特定字符
                    //将剩余的部分当作一个字串 放入array
                    if(pos==src.size())break;
                    array->push_back(src.substr(offset));
                    return array->size();
                }
                if(pos==offset)
                {
                    offset = pos+sep.size();
                    continue;
                }
                array->push_back(src.substr(offset,pos - offset));
                offset = pos+sep.size();
            }

            return array->size();
        }

        //读取文件内容 将读取到的内容放到一个buffer
        static bool ReadFile(const std::string &filename,std::string*buf)
        {
            std::ifstream ifs(filename,std::ios::binary);
            if(ifs.is_open()==false)
            {
                ERR_LOG("OPEN %s FILE FAILED",filename.c_str());
                return false;
            }
            size_t fsize = 0;
            ifs.seekg(0,ifs.end);//跳转读取位置到末尾
            fsize = ifs.tellg();//获取当前读写位置相对于起始位置的偏移量 从末尾偏移刚好就是文件大小
            ifs.seekg(0,ifs.beg);//跳转到起始位置
            buf->resize(fsize);//开辟文件大小的空间
            ifs.read(&(*buf)[0],fsize);
            if(ifs.good()==false)
            {
                ERR_LOG("READ %s FILE FAILED",filename.c_str());
                ifs.close();
                return false;
            }
            ifs.close();
            return true;
        }


        //向文件写入数据
        static bool WriteFile(const std::string &filename,const std::string &buf)
        {
            std::ofstream ofs(filename,std::ios::binary|std::ios::trunc);
            if(ofs.is_open()==false)
            {
                ERR_LOG("OPEN %s FILE FAILED",filename.c_str());
                return false;
            }
            ofs.write(buf.c_str(),buf.size());
            if(ofs.good()==false)
            {
                ERR_LOG("WRITE %s FILE FAILED",filename.c_str());
                ofs.close();
                return false;
            }
            ofs.close();
            return true;
        }

        //URL编码  避免url中资源路径与查询字符串中的特殊字符与http请求中的特殊字符产生歧义
        //编码格式 将特殊字符的ascii值转换为两个十六进制字符 前缀%  c++ -> c%2B%2B
        //不编码的特殊字符：  .-_~ 字母与数字 
        //RFC3986 编码格式 %HH
        //W3C  查询字符串中的空格要被转换为 +  解码则是+转空格
        static std::string UrlEncode(const std::string url,bool convert_space_to_plus)
        {
            std::string res;
            for(auto &c:url)
            {
                if(c=='.'||c=='-'||c=='_'||c=='~'||isalnum(c))
                {
                    res+=c;
                    continue;
                }
                if(c==' '&&convert_space_to_plus)
                {
                    res+='+';
                    continue;
                }
                char tmp[4] = {0};
                snprintf(tmp,4,"%%%02X",c);
                res+=tmp;
            }

            return res;
        }

        static char HexToI(char c)
        {
            if(c>='0'&&c<='9')
                return c-'0';
            else if(c>='A'&&c<='Z')
                return c-'A'+10;
            else if(c>='a'&&c<='z')
                return c-'a'+10;
            else
                return -1;
        }

        //URL解码  
        static std::string UrlDecode(const std::string url,bool convert_plus_to_space)
        {
            std::string res;
            //遇到%则将紧随其后的两个字符转为数字 第一个数字左移四位再加上第二个数字
            for (int i = 0;i<url.size();i++)
            {
                if(url[i]=='+'&&convert_plus_to_space)
                {
                    res+=' ';
                    continue;
                }
                if(url[i]=='%'&&(i+2)<url.size())
                {
                    char v1 = HexToI(url[i+1]);
                    char v2 = HexToI(url[i+2]);
                    char v = (v1<<4)+v2;
                    res+=v;
                    i+=2;
                    continue;
                }
                res+=url[i];
            }
            return res;
        }

        //相应状态码的描述信息获取
        static std::string StatuDesc(int statu)
        {

            auto it = _statu_message.find(statu);
            if(it!=_statu_message.end())
                return it->second;
            return "Unknow";
        }

        //根据文件后缀获取mime
        static std::string ExtMime(const std::string &filename)
        {
            //先获取文件扩展名 在获取mime
            size_t pos = filename.find_last_of('.');
            if(pos == std::string::npos)
                return "application/octet-stream";
            std::string ext = filename.substr(pos);
            auto it = _mime_message.find(ext);
            if(it==_mime_message.end())
                return "application/octet-stream";
            return it->second;
        }

        //判断文件是否为目录
        static bool IsDirectory(const std::string &filename)
        {
            struct stat st;
            int ret = stat(filename.c_str(),&st);
            if(ret<0)
            {
                return false;
            }
            return S_ISDIR(st.st_mode);
        }

        //判断一个文件是否为普通文件
        static bool IsRegular(const std::string &filename)
        {
            struct stat st;
            int ret = stat(filename.c_str(),&st);
            if(ret<0)
            {
                return false;
            }
            return S_ISREG(st.st_mode);
        }
        
        //http请求的资源路径有效性判断
        // /index.html   前面的/为相对根目录  映射的是某个服务器上的子目录
        //客户端只能请求相对根目录中的资源 其他地方的资源不予理会
        //  /../login  ..会让路径的查找跑到相对根目录之外 这是不合理的 不安全的
        static bool VaildPath(const std::string &path)
        {
            //按照/进行路径分割 根据有多少子目录 计算目录深度有多少层 深度不能小于0
            std::vector<std::string> subdir;
            Split(path,"/",&subdir);
            int level  = 0;
            for(auto& dir :subdir)
            {
                if(dir=="..")
                {
                    //任意一层小于0就认为有问题
                    level--;
                    if(level<0)
                        return false;
                }
                else
                    level++;
            }
            return true;
        }
};




class HttpRequest
{
    public:
        std::string _method;            //请求方法
        std::string _path;              //资源路径
        std::string _version;           //协议版本
        std::string _body;              //请求正文
        std::smatch _matches;           //资源路径的正则提取数据
        std::unordered_map<std::string,std::string> _headers;   //头部字段
        std::unordered_map<std::string,std::string> _params;    //查询字符串

    public:
        HttpRequest():_version("HTTP/1.1"){}

        void ReSet()
        {
            _method.clear();
            _path.clear();
            _version="HTTP/1.1";
            _body.clear();
            std::smatch match;
            _matches.swap(match);
            _headers.clear();
            _params.clear();
        }

        //插入头部字段
        void SetHeader(const std::string &key,const std::string& val) 
        {
            _headers.insert(std::make_pair(key,val));
        }

        //判断是否存在指定头部字段
        bool HasHeaders(const std::string &key) const
        {
            auto it = _headers.find(key);
            if(it==_headers.end())
                return false;
            return true;
        }

        //获取指定头部字段的值
        std::string GetHeader(const std::string &key) const
        {
            auto it = _headers.find(key);
            if(it==_headers.end())
                return "";
            return it->second;
        }

        //插入查询字符串
        void SetParam(const std::string &key,const std::string& val)
        {
            _params.insert(std::make_pair(key,val));
        }

        //是否有指定的查询字符串
        bool HasParam(const std::string &key) const
        {
            auto it = _params.find(key);
            if(it==_params.end())
                return false;
            return true;
        }

        //获取指定的查询字符串
        std::string GetParam(const std::string &key) const
        {
            auto it = _params.find(key);
            if(it==_params.end())
                return "";
            return it->second;
        }

        //获取正文长度
        size_t ContentLength() const 
        {
            bool ret = HasHeaders("Content-Length");
            if(ret == false)
                return 0;
            std::string clen = GetHeader("Content-Length");
            return std::stol(clen);
        }

        //是否为短链接
        bool Close() const
        {
            if((HasHeaders("Connection")==true)&&(GetHeader("Connection")=="keep-alive"))
                return false;
            return true;
        }
};






class HttpResponse
{
    public:
        int _statu;
        bool _redirect_flag;
        std::string _body;
        std::string _redirect_url;
        std::unordered_map<std::string,std::string> _headers;
    public:
        HttpResponse():_redirect_flag(false),_statu(200){}
        HttpResponse(int statu):_redirect_flag(false),_statu(statu){}

        void ReSet()
        {
            _statu = 200;
            _redirect_flag = false;
            _body.clear();
            _redirect_url.clear();
            _headers.clear();
        }

        //插入头部字段
        void SetHeader(const std::string &key,const std::string& val)
        {
            _headers.insert(std::make_pair(key,val));
        }

        //判断是否存在指定头部字段
        bool HasHeaders(const std::string &key)
        {
            auto it = _headers.find(key);
            if(it==_headers.end())
                return false;
            return true;
        }

        //获取指定头部字段的值
        std::string GetHeader(const std::string &key)
        {
            auto it = _headers.find(key);
            if(it==_headers.end())
                return "";
            return it->second;
        }

        void SetContent(const std::string &body,const std::string &type = "text/html")
        {
            _body = body;
            SetHeader("Content-Type",type);
        }

        void SetRedirect(const std::string &url,int statu = 302)
        {
            _statu = statu;
            _redirect_flag = true;
            _redirect_url = url;

        }

        //判断是否为短链接
        bool Close()
        {
            if(HasHeaders("Connection")==true&&GetHeader("Connection")=="keep-alive")
                return false;
            return true;
        }
};


typedef enum 
{
    RECV_HTTP_ERROR,
    RECV_HTTP_LINE,
    RECV_HTTP_HEAD,
    RECV_HTTP_BODY,
    RECV_HTTP_OVER
}HttpRecvStatu;

#define MAX_LINE 8192

class HttpContext
{
    private:
        int _resp_statu;                //响应状态码
        HttpRecvStatu _recv_statu;      //当前接受及解析的阶段状态
        HttpRequest _request;          //已经解析得到的请求信息

    private:

        //解析请求行 
        // 0:GET /sbhghx/login?user=ghx&pass=123456 HTTP/1.1
        // 1:GET
        // 2:/sbhghx/login
        // 3:user=ghx&pass=123456
        // 4:HTTP/1.1
        bool ParseHttpLine(const std::string &line)
        {
            std::smatch matches;
            std::regex e("(GET|HEAD|POST|PUT|DELETE) ([^?]*)(?:\\?(.*))? (HTTP/1\\.[01])(?:\n|\r\n)?",std::regex::icase);

            bool ret = std::regex_match(line,matches,e);

            if(ret ==false)
            {
                _recv_statu = RECV_HTTP_ERROR;
                _resp_statu = 400;      //BAD REQUEST
                return false;
            }

            //请求方法的获取
            _request._method = matches[1];
            std::transform(_request._method.begin(),_request._method.end(),_request._method.begin(),::toupper);
            //资源路径的获取 需要url解码操作 但不用+转空格
            _request._path = Util::UrlDecode(matches[2],false);
            //协议版本的获取
            _request._version = matches[4];

            std::vector<std::string> query_string_array;
            std::string query_string = matches[3];
            //查询字符串的格式 key=val&key=val.......  先用&进行分割得到各个字串
            Util::Split(query_string,"&",&query_string_array);
            //针对各个字串 以=进行分割 得到key和val
            for(auto & str: query_string_array)
            {
                size_t pos = str.find("=");
                if(pos==std::string::npos)
                {
                    _recv_statu = RECV_HTTP_ERROR;
                    _resp_statu = 400;      //BAD REQUEST
                    return false;
                }
                std::string key = Util::UrlDecode(str.substr(0,pos),true);
                std::string val = Util::UrlDecode(str.substr(pos+1),true);
                _request.SetParam(key,val);
            }
            return true;
        }

        bool RecvHttpLine(Buffer* buf)
        {
            if(_recv_statu!=RECV_HTTP_LINE)return false;
            //获取一行数据
            std::string line = buf->GetLineAndPop();
            //考虑 缓冲区的数据不足一行||获取的一行数据超大
            if(line.size()==0)
            {
                //不足一行 则需要判断缓冲区的可读数据长度有多长 若很长都不足一行则证明有问题
                if(buf->ReadAbleSize()>MAX_LINE)
                {
                    _recv_statu = RECV_HTTP_ERROR;
                    _resp_statu = 414;          //URI TOO LONG
                    return false;
                }
                //不足一行但不多 等新数据到了
                return true;
            }

            if(line.size()>MAX_LINE)
            {
                _recv_statu = RECV_HTTP_ERROR;
                _resp_statu = 414;          //URI TOO LONG
                return false;
            }

            bool ret = ParseHttpLine(line);
            if(ret == false)
                return false;

            //首行处理完毕 进入头部获取阶段
            _recv_statu = RECV_HTTP_HEAD;
            return true;
        }


        bool RecvHttpHead(Buffer* buf)
        {
            if(_recv_statu!=RECV_HTTP_HEAD)return false;
            //一行一行取出数据 直到遇到空行  头部格式 key: val\r\nkey: val\r\n.....
            while(1)
            {            
                //获取一行数据
                std::string line = buf->GetLineAndPop();
                //考虑 缓冲区的数据不足一行||获取的一行数据超大
                if(line.size()==0)
                {
                    //不足一行 则需要判断缓冲区的可读数据长度有多长 若很长都不足一行则证明有问题
                    if(buf->ReadAbleSize()>MAX_LINE)
                    {
                        _recv_statu = RECV_HTTP_ERROR;
                        _resp_statu = 414;          //URI TOO LONG
                        return false;
                    }
                    //不足一行但不多 等新数据到了
                    return true;
                }

                if(line.size()>MAX_LINE)
                {
                    _recv_statu = RECV_HTTP_ERROR;
                    _resp_statu = 414;          //URI TOO LONG
                    return false;
                }
                if(line=="\n"||line=="\r\n")
                {
                    break;
                }
                bool ret = ParseHttpHead(line);
                if(ret == false)
                    return false;
            }
            //头部处理完毕 进入正文获取阶段
            _recv_statu = RECV_HTTP_BODY;
            return true;
        }

        bool ParseHttpHead(std::string &line)
        {
            if(line.back()=='\n')line.pop_back();
            if(line.back()=='\r')line.pop_back();
            size_t pos = line.find(": ");
            if(pos==std::string::npos)
            {
                _recv_statu = RECV_HTTP_ERROR;
                _resp_statu = 400;          //BAD REQUEST
                return false;
            }
            std::string key = line.substr(0,pos);
            std::string val = line.substr(pos+2);
            _request.SetHeader(key,val);
            return true;
        }

        bool RecvHttpBody(Buffer* buf)
        {
            if(_recv_statu!=RECV_HTTP_BODY)return false;

            //获取正文长度
            size_t context_length = _request.ContentLength();
            if(context_length==0)
            {
                //则请求接收解析完毕
                _recv_statu = RECV_HTTP_OVER;
                return true;
            }
            //当前已经接受了多少正文 就是_request._body中放了多少数据
            size_t real_len = context_length - _request._body.size();
            //接受正文放到body中  并考虑当前缓冲区中的数据是否是全部正文
            //  缓冲区中的数据 包含了当前请求的所有正文 则取出所需的数据
            if(buf->ReadAbleSize()>=real_len)
            {
                _request._body.append(buf->ReadPosition(),real_len);
                buf->MoveReadOffset(real_len);
                _recv_statu = RECV_HTTP_OVER;
                return true;
            }
            //  缓冲区中的数据 无法满足当前正文的需要 数据不足，取出数据，等待新数据到来
            _request._body.append(buf->ReadPosition(),buf->ReadAbleSize());
            buf->MoveReadOffset(buf->ReadAbleSize());
            
            return true;
        }

    public:
        HttpContext():_resp_statu(200),_recv_statu(RECV_HTTP_LINE){}

        void ReSet()
        {
            _resp_statu = 200;
            _recv_statu = RECV_HTTP_LINE;
            _request.ReSet();
        }
        int RespStatu()
        {
            return _resp_statu;
        }

        HttpRecvStatu RecvStatu()
        {
            return _recv_statu;
        }

        HttpRequest &Request()
        {
            return _request;
        }

        //接收并解析HTTP请求
        void RecvHttpRequest(Buffer* buf)
        {
            //不同的状态做不同的事情 不要break 处理完首行后 应该立即处理头部 而不是退出等待
            switch(_recv_statu)
            {
                case RECV_HTTP_LINE:
                    RecvHttpLine(buf);
                case RECV_HTTP_HEAD:
                    RecvHttpHead(buf);
                case RECV_HTTP_BODY:
                    RecvHttpBody(buf);
            }
            return;
        }
};


class HttpServer
{
    private:
        using Handler = std::function<void(const HttpRequest&,HttpResponse*)>;
        using Handlers = std::vector<std::pair<std::regex,Handler>>;
        Handlers _get_route;
        Handlers _post_route;
        Handlers _put_route;
        Handlers _delete_route;
        std::string _basedir;           //静态资源根目录
        TcpServer _server;

    private:
        void ErrorHandler(const HttpRequest& req,HttpResponse* rsp)
        {
            //组织错误展示页面
            std::string body;
            body+="<html>";
            body+="<head>";
            body+="<meta http-equiv='Content-Type' content='text/html;charset=utf-8'>";
            body+="</head>";
            body+="<body>";
            body+="<h1>";
            body+=std::to_string(rsp->_statu);
            body+=" ";
            body+=Util::StatuDesc(rsp->_statu);
            body+="</h1>";
            body+="</body>";
            body+="</html>";
            //将页面数据当成响应正文放入rsp
            rsp->SetContent(body,"text/html");
        }

        //将httpresponse中的要素进行组织发送
        void WriteResponse(const PtrConnection& conn,const HttpRequest& req,HttpResponse& rsp)
        {
            //先完善头部字段
            if(req.Close()==true)
            {
                rsp.SetHeader("Connection","close");
            }
            else
            {
                rsp.SetHeader("Connection","keep-alive");
            }
            if(rsp._body.empty()==false&&rsp.HasHeaders("Content-Length")==false)
            {
                rsp.SetHeader("Content-Length",std::to_string(rsp._body.size()));
            }
            if(rsp._body.empty()==false&&rsp.HasHeaders("Content-Type")==false)
            {
                rsp.SetHeader("Content-Type","application/octet-stream");
            }
            if(rsp._redirect_flag==true)
            {
                rsp.SetHeader("Location",rsp._redirect_url);
            }
            //将rsp的要素按照http协议进行组织
            std::stringstream rsp_str;
            rsp_str << req._version << " " << std::to_string(rsp._statu) << " " << Util::StatuDesc(rsp._statu) << "\r\n";
            for(auto &head:rsp._headers)
            {
                rsp_str<<head.first<<": "<<head.second<<"\r\n";
            }
            rsp_str<<"\r\n";
            rsp_str<<rsp._body;
            //发送数据
            conn->Send(rsp_str.str().c_str(),rsp_str.str().size());
        }

        //判断一个请求是否是静态资源请求
        bool IsFileHandler(const HttpRequest& req)
        {
            //必须设置了静态资源根目录
            if(_basedir.empty())
                return false;
            //请求方法必须是GET||HEAD
            if(req._method!="GET"&&req._method!="HEAD")
                return false;
            //请求的资源路径必须合法
            if(Util::VaildPath(req._path) == false)
                return false;
            //请求的资源必须存在    且是普通文件
            //如果请求的是目录  / /image/ 默认追究index.html
            //不要忘记前缀的相对根目录 将请求路径转为实际存在的路径
            std::string req_path = _basedir + req._path;//避免直接修改请求资源的路径 创建临时对象
            if(req._path.back()=='/')
                req_path += "index.html";

            if(Util::IsRegular(req_path)==false)
                return false;

            //req._path = req_path;

            return true;
        }

        //静态资源请求  将静态资源的数据读出 放到rsp的body 设置mime
        void FileHandler(const HttpRequest& req,HttpResponse* rsp)
        {
            std::string req_path = _basedir + req._path;//避免直接修改请求资源的路径 创建临时对象
            if(req._path.back()=='/')
                req_path += "index.html";

            bool ret = Util::ReadFile(req_path,&rsp->_body);
            if(ret == false)
                return ;
            std::string mime = Util::ExtMime(req_path);
            rsp->SetHeader("Content-Type",mime);
            return ;
        }

        //功能性请求的分类处理
        void Dispatcher(HttpRequest& req,HttpResponse* rsp,Handlers &handlers)
        {
            //在对应请求方法的路由表中 查找是否含有对应资源请求的处理函数 有则调用 否则返回404
            //idea:路由表存储的键值对  正则表达式与处理函数
            //使用正则表达式 对请求的资源路径进行正则匹配 匹配成功就使用对应函数进行处理
            // /numbers/(\d+)     /numbers/12345
            for(auto& handler:handlers)
            {
                const std::regex& re = handler.first;
                const Handler& functor = handler.second;
                bool ret = std::regex_match(req._path,req._matches,re);
                if(ret==false)
                    continue;
                return functor(req,rsp);//调用传入请求信息和空的rsp执行处理函数
            }
            rsp->_statu = 404;
        }

        //路由匹配
        void Route(HttpRequest& req,HttpResponse* rsp)
        {
            //对请求进行分辨 是静态资源请求还是功能性请求
            //  静态资源请求则进行静态资源的处理
            //  功能性则需要通过几个请求路由表来确定是否有处理函数
            //  若既不是静态同时又没有功能性处理函数 则返回405
            if(IsFileHandler(req)==true)
            {
                //是静态资源请求
                return FileHandler(req,rsp);
            }
            if(req._method=="GET"||req._method=="HEAD")
            {
                return Dispatcher(req,rsp,_get_route);
            }
            else if(req._method=="POST")
            {
                return Dispatcher(req,rsp,_post_route);
            }
            else if(req._method=="PUT")
            {
                return Dispatcher(req,rsp,_put_route);
            }
            else if(req._method=="DELETE")
            {
                return Dispatcher(req,rsp,_delete_route);
            }
            else
            {
                rsp->_statu=405; //METHOT NOT ALLOWED
            }
        }

        //设置上下文
        void OnConnected(const PtrConnection& conn)
        {
            conn->SetContext(HttpContext());
            DBG_LOG("NEW CONNECTION  %p",conn.get());
        }  

        //缓冲区数据解析
        void OnMessage(const PtrConnection& conn,Buffer* buffer)
        {
            while(buffer->ReadAbleSize()>0)
            {
                //获取上下文
                HttpContext* context  = conn->GetContext()->get<HttpContext>();
                //通过上下文对缓冲区数据进行解析 得到httprequest对象 
                //  如果数据解析出错 直接回复出错响应
                //  如果解析正常且请求已经获取完毕 才开始去进行处理
                context->RecvHttpRequest(buffer);
                HttpRequest& req = context->Request();
                HttpResponse rsp(context->RespStatu());
                if(context->RespStatu()>=400)
                {
                    //进行错误响应 关闭连接
                    ErrorHandler(req,&rsp);          //填充一个错误显示页面数据到rsp
                    WriteResponse(conn,req,rsp);    //组织响应发送给客户端
                    context->ReSet();
                    buffer->MoveReadOffset(buffer->ReadAbleSize());
                    conn->Shutdown();               //关闭连接
                    return;
                }
                if(context->RecvStatu()!=RECV_HTTP_OVER)
                {
                    //当前请求还未接受完整 直接退出 等新数据到来再处理
                    return;
                }
                //请求路由 + 业务处理
                Route(req,&rsp);
                //对httpresponse进行组织发送
                WriteResponse(conn,req,rsp);
                //重置上下文
                context->ReSet();
                //根据长短连接判断是否关闭连接 或 继续处理
                if(rsp.Close()==true)
                    conn->Shutdown();//短链接直接关闭
            }
            return;
        }

    public:
        HttpServer(int port,int timeout = DEFAULT_TIMEOUT):_server(port)
        {
            _server.EnableInactiveRelease(timeout);
            _server.SetConnectedCallback(std::bind(&HttpServer::OnConnected,this,std::placeholders::_1));
            _server.SetMessageCallback(std::bind(&HttpServer::OnMessage,this,std::placeholders::_1,std::placeholders::_2));
        }

        void SetBaseDir(const std::string& path)
        {
            assert(Util::IsDirectory(path)==true);
            _basedir = path;
        }

        //设置||添加 请求（正则表达式）与处理函数的映射关系
        void Get(const std::string &pattern,const Handler& handler)
        {
            _get_route.push_back(std::make_pair(std::regex(pattern),handler));
        }
        void Post(const std::string &pattern,const Handler& handler)
        {
            _post_route.push_back(std::make_pair(std::regex(pattern),handler));
        }                        
        void Put(const std::string &pattern,const Handler& handler)
        {
            _put_route.push_back(std::make_pair(std::regex(pattern),handler));
        }                                
        void Delete(const std::string &pattern,const Handler& handler)
        {
            _delete_route.push_back(std::make_pair(std::regex(pattern),handler));
        }

        void SetThreadCount(int count)
        {
            _server.SetThreadCount(count);
        }

        void Listen()
        {
            _server.Start();
        }
};